linux-kernel - [PATCH V2 6/6] nvmem: u-boot-env: post process "ethaddr" env variable

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Date:   Wed, 11 Jan 2023 08:31:02 +0100
From:   Rafał Miłecki <zajec5@...il.com>
To:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
Cc:     Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Michael Walle <michael@...le.cc>, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        u-boot@...ts.denx.de,
        Rafał Miłecki <rafal@...ecki.pl>
Subject: [PATCH V2 6/6] nvmem: u-boot-env: post process "ethaddr" env variable

From: Rafał Miłecki <rafal@...ecki.pl>

U-Boot environment variables are stored in ASCII format so "ethaddr"
requires parsing into binary to make it work with Ethernet interfaces.

This includes support for indexes to support #nvmem-cell-cells = <1>.

Signed-off-by: Rafał Miłecki <rafal@...ecki.pl>
---
 drivers/nvmem/layouts/Kconfig      |  1 +
 drivers/nvmem/layouts/u-boot-env.c | 25 +++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/drivers/nvmem/layouts/Kconfig b/drivers/nvmem/layouts/Kconfig
index 8a38c514943a..566b4f25630d 100644
--- a/drivers/nvmem/layouts/Kconfig
+++ b/drivers/nvmem/layouts/Kconfig
@@ -23,6 +23,7 @@ config NVMEM_LAYOUT_ONIE_TLV
 config NVMEM_LAYOUT_U_BOOT_ENV
 	bool "U-Boot environment variables support"
 	select CRC32
+	select GENERIC_NET_UTILS
 	help
 	  U-Boot stores its setup as environment variables. This driver adds
 	  support for verifying & exporting such data. It also exposes variables
diff --git a/drivers/nvmem/layouts/u-boot-env.c b/drivers/nvmem/layouts/u-boot-env.c
index 95c314553952..e99b853a44c4 100644
--- a/drivers/nvmem/layouts/u-boot-env.c
+++ b/drivers/nvmem/layouts/u-boot-env.c
@@ -4,6 +4,8 @@
  */
 
 #include <linux/crc32.h>
+#include <linux/etherdevice.h>
+#include <linux/if_ether.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/nvmem-consumer.h>
@@ -36,6 +38,27 @@ struct u_boot_env_image_broadcom {
 	uint8_t data[];
 } __packed;
 
+static int u_boot_env_read_post_process_ethaddr(void *context, const char *id, int index,
+						unsigned int offset, void **data, size_t *bytes)
+{
+	u8 mac[ETH_ALEN];
+
+	if (*bytes != 3 * ETH_ALEN - 1)
+		return -EINVAL;
+
+	if (!mac_pton(*data, mac))
+		return -EINVAL;
+
+	if (index)
+		eth_addr_add(mac, index);
+
+	/* We need *smaller* buffer so don't bother to krealloc() */
+	ether_addr_copy(*data, mac);
+	*bytes = ETH_ALEN;
+
+	return 0;
+}
+
 static int u_boot_env_parse_data(struct device *dev, struct nvmem_device *nvmem, uint8_t *buf,
 				 size_t data_offset, size_t data_len)
 {
@@ -67,6 +90,8 @@ static int u_boot_env_parse_data(struct device *dev, struct nvmem_device *nvmem,
 		info.offset = data_offset + value - data;
 		info.bytes = strlen(value);
 		info.np = of_get_child_by_name(np, info.name);
+		if (!strcmp(var, "ethaddr"))
+			info.read_post_process = u_boot_env_read_post_process_ethaddr;
 
 		err = nvmem_add_one_cell(nvmem, &info);
 		if (err) {
-- 
2.34.1